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Rabu, 26 Mei 2010

MARINE ALGAL POLYPHENOLICS

Polyphloroglucinol phenolics are the best known example of chemical deterrents against herbivores in temperate marine systems. However, most of the research on these compounds has been done in North America, where phenolic levels in algae are often low. I show here that algae in the Orders Fucales and Laminariales in temperate Australia and New Zealand typically contain very high levels of polyphenolics-much higher than species in these orders in North America. The median value for the distribution of mean phenolic levels for 25 North American species is 1.33% total phenolics (dry wt.); for 37 Australasian species, the median is 6.20%. Significant spatial, temporal, and intraplant variation in phenolic content occurs in a number of species in Australasia, but this does not significantly alter my major conclusion.

Phenolic levels in drift algae (an important food source for some herbivores) detached for up to two weeks are also not significantly different from living, attached plants. Many species in the Fucales in Australasia also contain non-polyphenolic secondary metabolites that are not found in North American species. Thus herbivores in Australasia face greater amounts, and a greater range,of putative chemical defenses in brown algae than do herbivores in similar systems in North America. Any general theory for the evolution of marine plant/herbivore interactions must take into account such broad-scale biogeographical (and taxonomic) patterns.

The diversity and intensity of selection pressure on organisms has been described as varying predictably across biogeographic zones, generally increasing with decreasing latitude. Apparent effects of this increased selective pressure in the tropics include patterns in species diversity (Pianka 1966), diversity and quantity of allelochemicals (Bakus and Green 1974; Levin 1971, 1976; Levin and York 1978; Hay and Fenical 1988; Coley and Aide 1991; Hay and Steinberg in press), predation intensity, inferred antipredatory morphological structures (Vermeij 1978; Jeanne 1979; Bertness et al. 1981; Heck and Wilson 1987) and herbivory (Levin 1976; Lubchenco and Gaines 1981; Gaines and Lubchenco 1982; Steneck 1988; Hay and Steinberg in press). In the marine environment, herbivory is most intense at low latitudes (Vermeij 1978; Lubchenco and Gaines 1981 ; Steneck 1988 ; Hay and Steinberg in press). Algal chemical defenses generally Offprint requests to: N.M.

Targett parallel this latitudinal variation in herbivory with increasing concentration and diversity of allelochemicals with decreasing latitude (Hay and Fenical 1988; Hay and Steinberg in press). Phloroglucinol-based polyphenolics (phlorotannins, see Ragan and Glombitza 1986), antifeedant allelochemicals which occur exclusively in brown algae (Phaeophyta), have been reported as an exception to this trend, increasing in concentration with increasing latitude (Steinberg and Paul 1990; Van Alstyne and Paul 1990; Steinberg et al. 1991 ; Steinberg and Van Altena in press).

This is in contrast to terrestrial data on condensed tannins for broad leaved forest species, which show that temperate species have lower phenolic concentrations than tropical ones (Coley and Aide, 1991 and references therein). In marine temperate regions, where considerable data exist on phlorotannin concentrations, brown algae are characterized as either high or low phenolic species. High phenolic species are defined as those with phenolic concentrations > 2% of their dry weight, the threshold level at which herbivory is typically deterred (Swain 1979; Geiselman and McConnell 1981 ; Steinberg 1988). However, a high degree of inter- and intraspecific variability in phenolic concentration has been observed (Ragan and Glombitza 1986; Steinberg 1986, 1988, 1989).

Phenolic concentrations in tropical phaeophytes have been reported only from Indo-Pacific species; therefore, a less complete picture is available for tropical than for temperate browns (Hay and Fenical 1988; Steinberg and Paul 1990; Van Alstyne and Paul 1990; Steinberg 1986, 1989; Steinberg et al. 1991 ; Steinberg and Van Altena in press). In the Indo-Pacific, phenolic concentrations have been found to be low, although Padina spp. from Magnetic Island, Australia (Steinberg et al. 1991) and individual plants in two other genera (Lobophora and Dictyopteris) were noted as exceptions (Steinberg and Paul 1990). Although brown algal phenolic concentrations have not been determined for any Caribbean species, patterns of herbivore preference have been used to suggest that polyphenolics might be high in some species (Norris and Fenical 1982). We examined phenolic levels in tropical phaeophytes from both the Caribbean and western Pacific and in selected species from the temperate western Atlantic and eastern Pacific (i.e. both coasts of North America). These levels were compared to literature values to determine: 1. Are there latitudinal trends in phenolic concentrations? 2. Are there interoceanic differences between tropical Old World (Indo-Pacific)and Neotropical (Caribbean) phaeophyte phenolic concentrations? 3. Does the magnitude of intraspecific phenolic variability in tropical and temperate phaeophytes overshadow observed latitudinal trends?


Tropical Species
The Caribbean phaeophytes (orders Fucales and Dictyotales) that we examined had phenolic concentration levels ranging from 1.34% to 14.92% dry weight. Caribbean Fucales all had high phenolic concentrations (> 2 %) and tested positive for phloroglucinol derivatives. Two of the four Caribbean Dictyotales examined (Stypopodium zonale and Lobophora variegata in each of its three forms, Coen and Tanner 1989) also had high phenolic concentrations. The dry weight phenolic concentration values for the Lobophora forms and for Stypopodium (8.33% 13.39% and 14.92% respectively) far exceeded all previously reported values for species in this order. Thus, our data from Caribbean phaeophytes in which six of eight species produced phenolic concentrations in excess of 2% (3.37%-14.92%) show that high phlorotannin concentrations are not limited to temperate species. Tropical interocean differences are evident when comparing phenolic concentration values for phaeophyte genera common to the Indo-Pacific and Caribbean. Lobophora variegata, the only species examined in this study that is common to the tropical areas listed, showed low phenolic values for Pacific (0.81%, Hawaii, Table 1) and Indo-Pacific (<2%, p="0.006)," p="0.002)"> 2% dry weight), while species in the orders Laminariales and Dictyotales typically have low levels (Steinberg 1985, 1989; Ragan and Glombitza 1986; Steinberg and Paul 1990; Van Alstyne and Paul 1990; Steinberg et al. 1991 ; Steinberg and Van Altena in press). Earlier studies also show that polyphenolic levels in tropical Fucales and Dictyotales from the Indo-Pacific are low (Steinberg 1986, 1989; Hay and Fenical 1988; Steinberg and Paul 1990; Van Alstyne and Paul 1990; Steinberg et al. 1991). Our results clearly demonstrate that species in the tropics can be high in phenolics. Data from our study and from the literature, where extraction and quantification procedures allow comparisons to be made, also indicate that intraspecific variability may be as high as interspecific variability. Of the phenolic values obtained, most striking were the values obtained for the three forms of Lobophora (Coen and Tanner 1989) and for Stypopodium (8.33-13.39% and 14.92% dry weight respectively). Phloroglucinol and a variety of phenolic acids have been reported from Lobophora variegata (form not specified) collected in Brazil (Legaz et al. 1985). Acetate-derived phenolic lipids have been described from Lobophora papenfussii (Gerwick and Fenical 1982) and their presence in Lobophora variegata (form unspecified) from the Florida Keys has been hypothesized (Paul and Hay 1986). However, higher-molecular-weight phlorotannins are also evident (Folin-Denis test, Lindt test, 1H NMR) in molecular sizing
experiments done on aqueous extracts from each of the three forms of Lobophora collected in Belize (Boettcher and Targett unpublished data). Fresh Stypopodium is known to contain a series of primarily mevalonatederived low-molecular-weight phenolic metabolites (<> 100,000Da (Boettcher and Targett unpublished data).

The absence of a latitudinal phlorotannin trend between Caribbean tropical and temperate phaeophytes and the presence of site-specific phlorotannin variability within species suggests that other factors may play a more critical role within a biogeographic region in determining phenolic concentrations. Variability in phenolic concentration may be influenced by extrinsic factors such as salinity (Ragan and Glombitza 1986), nutrient availability (Ilvessalo and Tuomi 1989), herbivore intensity (Van Alstyne 1988) and season (Ragan and Jensen 1978 ; Ragan and Glombitza 1986). Intrinsic plant factors such as size (Denton et al. 1990), age (Pederson 1984), and tissue type (Steinberg 1984; Tugwell and Branch 1989; Tuomi et al. 1989) may also play a role. The magnitude of the variation in phenolic concentration is often high enough to alter the palatibility of plants to herbivores (Swain 1979; Geiselman and McConnell 1981; Steinberg 1988). Studies regarding the effect of plant phlorotannin concentration on marine tropical herbivores have yielded conflicting results. Van Alstyne and Paul (1990) showed that phlorotannins from temperate species are effective deterrents against some tropical herbivores when they are incorporated into tropical analogues at concentrations > 2% dry wt, while Steinberg et al. (1991) showed that quantitative variability in temperate and tropical algal phenolic levels do not correlate with the susceptibility of these algae to herbivory. These and other studies make supportive arguments based upon the assumption that all tropical phaeophytes are typically low in phenolics and invoke physiological and cost arguments as explanations for their low concentrations (Steinberg 1986; Hay and Fenical 1988; Van Alstyne 1988; Steinberg and Paul 1990; Van Alstyne and Paul 1990; Steinberg et al. 1991; Hay and Steinberg in press; Steinberg and Van Altena in press). Our study shows that phenolics can be present in high and variable concentrations in tropical Caribbean phaeophytes, and thus the assumption that phlorotannins are of little consequence in tropical marine plant-herbivore interactions because of their low concentrations (Steinberg 1986; Hay and Fenical 1988; Van Alstyne 1988; Steinberg and Paul 1990; Van Alstyne and Paul 1990; Steinberg et al. 1991) is premature.

Our results in combination with previously published data suggest that there is an interoceanic difference between phenolic concentrations in tropical Indo-Pacific phaeophytes and Caribbean phaeophytes. Grazing intensity is higher in the Pacific and Indian oceans than in ecologically similar communities in the Atlantic (Vermeij 1978; Estes and Steinberg 1988; Steinberg and Van A1-tena in press). Grazing intensity thus correlates negatively with our observations of phaeophyte phenolic concentrations and calls into question the role of phlorotannins in defense. However, other extrinsic and intrinsic factors may confound the interpretation and should be examined (Bernays et al. 1989). To explain these differences and those in temperate and tropical marine plant-herbivore interactions, it is now evident that more subtle within-plant (Zucker 1983; Gaines 1985; Lewis et al. 1987; Coen and Tanner 1989) and among-herbivore (Gaines 1985; Hay et al. 1987; Horn 1989) characteristics must be examined. These include phenotypic variation in phenolic concentrations, phlorotannin size distributions, induction of phenolics by herbivores, as well as herbivore features such as gut pH and the presence of gut surfactants. Studies such as these will allow a further comparison between the importance of biological/physical factors and geographic distribution in determining phlorotannin concentrations.

Keterangan Gambar :
1. Jenis Alga Laut
2. Struktur Serotonin
3. Spirulina salah satu hasil alga laut


Nb* Dari banyak sumber bacaan.

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Brown Alga Sargassum asperifolium

Marine organisms have yielded a variety of secondary metabolites that possess novel chemical structures and interesting pharmacological activities (Stonik and Elyalov, 1986). Recently, researchers have described a wide range of biological activities for algal compounds including antibiotic, anti-HIV, anticoagulant, anticonvulsant, anti-inflamnatory, antineoplastic, and antitumor (Ayyad et al., 2002; Lincolon et al., 1991).

A number of diterpenes and sterols have been isolated from the brown algae (Ayyad et al., 2001; Banaigs et al.,1983; Combaut et al., 1980; Enoki et al., 1982; Faulkner et al., 1977; Franciso et al., 1977). In the course of our investigation on the biologically active components of the sargassaceae algae, we report, the isolation and characterization of a new saringosterone (3), a known saringosterol (4), and a known diterpene dictyone (1) from the brown alga Sargassum asperifolium.

Abaout Sargassum

Where seen? The largest of our brown seaweeds, this golden leafy seaweed with strange air bladders is commonly encountered on our Southern shores, but rarely on our Northern shores. It grows on the rocky shores as well as on coral rubble. It appears to be seasonal, sometimes forming a luxuriant golden carpet that covers vast areas of the shore, and washing up on the high tide line in huge heaps. At other times, only short, sparsely bladed specimens are seen, on coral rubble or rocks.

Features: Sargassum is the largest and most plant-like brown seaweed on our shores. The 'stems' grow to about 20cm or longer. Attached to the stems are leaf-shaped blades and inflated air bladders. The 'leaves' may be narrow, broad or very small (1-5cm long). The small round to oval air bladders interspersed among the 'leaves' are often mistaken for fruits. Seaweeds don't produce fruits like seagrasses do. The sargassum's air bladders help the seaweed stay afloat, closer to sunlight. Thus, long pieces often form floating rafts even after they have broken off from their holdfast. Some sargassum species can reproduce by producing new plants from horizontal creeping 'stems'. This is an adaptation to living on slippery rocks at the splash zone of rocky shores.

According to AlgaeBase: there are more than 580 current Sargassum species.

Sargassum forest: Sargassum seaweeds are often covered with other tiny seaweeds growing on or entangled among the blades. In this tangled mess, all kinds of small creatures lurk, hiding from predator or prey, or both.

Human uses: Sargassum seaweeds are eaten by people, and used fish bait in basket traps, animal feed, fertiliser, insect repellent. Various species are used as medicine for ailments ranging from children's fever, cholesterol problems, cleansing the blood, skin ailments.

In the tropics, sargassum seaweeds are a significant source of alginates. They are also used as a component in animal feed and liquid plant food or plant biostimulants. Supplies come from harvested seaweeds, the seaweeds are not farmed.

Detail Of Sargassum asperifolium

Classification:

Empire : Eukaryota
Kingdom : Chromista
Subkingdom : Chromobiota
Infrakingdom : Heterokonta
Phylum : Heterokontophyta
Class : Phaeophyceae
Order : Fucales
Family : Sargassaceae
Genus : Sargassum
Species : Sargassum asperifolium Hering & G. Martens ex J. Agardh

Publication details
Sargassum asperifolium var. dissimile Grunow 1916: 27

Original publication:
Grunow, A. (1916). Additamenta ad cognitionem Sargassorum. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 66: 1-48, 136-185.

Type species
The type species (holotype) of the genus Sargassum is Sargassum bacciferum (Turner) C. Agardh.

Status of name
This name is of an entity that is currently accepted taxonomically.

Synonym(s)
No synonyms are currently included in AlgaeBase.

General environment
This is a marine species.

Detailed distribution with sources
(as Sargassum asperifolium var. dissimile Grunow)
Africa: Ethiopia (Papenfuss 1968).

NCBI Nucleotide Sequences
No sequences have been found on the NCBI site.

Nb* dari berbagai sumber bacaan.

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Investigation of the antifouling constituents from the brown alga Sargassum muticum (Yendo) Fensholt

By. Alexandra Bazes1, 5, *, Alla Silkina1, Philippe Douzenel2, Fabienne Faÿ1, Nelly Kervarec3, Danièle Morin1, Jean-Pascal Berge4 and Nathalie Bourgougnon1

1. Introduction
Engineered structures such as ships and marine platforms, as well as offshore rigs and jetties, are under constant attack from the marine environment. These structures need to be protected from the influences of the key elements of the marine environment such as saltwater, biological attack and temperature fluctuations. The settlement and accumulation of marine organisms on an inanimate substrate can cause large penalties to engineered structures. In heat exchangers, biofouling can clog systems and on ship hulls it can increase the hydrodynamic drag, lower the manoeuvrability of the vessel and increase the fuel consumption. This leads to increased costs within the shipping industry through the increased use of manpower, fuel, material and dry docking time (Abarzua & Jakubowski, 1995, Lambert et al., 2006, Chambers et al., 2006).

The process of biological fouling is often grouped in the literature into key growth stages which include an initial accumulation of adsorbed organics, the settlement and growth of pioneering bacteria creating a biofilm matrix and the subsequent succession of micro and macrofoulers (Wahl, 1989, Abarzua & Jakubowski, 1995, Yebra et al., 2004). Methods for inhibiting both organic and inorganic growth on wetted substrates are varied but most antifouling systems take the form of protective coatings. Unfortunately, operational profiles vary; hence the application of one universal coating to ship hulls is unlikely and specific coatings designed for the particular needs of certain exposure and operational profiles may need to be targeted individually. Heavy metals and booster biocides such as Irgarol 1051 and Diuron are not an environmentally acceptable alternative due to increased concerns over their toxicity, but do offer cost benefits (Chambers et al., 2006). The International Maritime Organisation (IMO) legislation and the increased legislation of local and regional pesticide control authorities are the largest driving forces for the design and implementation of nontoxic antifouling coatings (Chambers et al., 2006).

Biomimetics approach implies the use of the natural world as a model on which to base an engineering development. Marine organisms have been shown to use both physical and chemical methods to protect themselves from biofouling (Bakus et al., 1986, Davis et al., 1989, Wahl, 1989, Steinberg et al., 1998, Fusetani, 2004, Bazes et al., 2006).
The introduced macroalga Sargassum muticum (Yendo) Fensholt (Heterokonta, Fucales) is
found along the coasts of South Brittany (Critchley et al., 1990, Plouguerné et al., 2006). Similar to many other macroalgae, S. muticum may accumulate quantities of secondary metabolites (Hay & Fenical, 1988, Steinberg, 1992, Hay, 1996) generally assumed to be a chemical defence against grazers and bacterial colonisation (Sieburth & Conover, 1965, Hay & Fenical, 1988, Harlin, 1996, Plouguerné et al., 2006). The chemical composition of Sargassum has been studied extensively and phlorotannins (Kubo et al., 1992), phlorethols (Banaimoon, 1992), sterols (Harvey & Kennicutt, 1992) and dicotylpthalate (Sastry & Rao, 1995) have been isolated. Various extracts from this alga have shown biological activities, including bactericidal and fungicidal activities (Sastry & Rao, 1994, 1995, Hellio et al., 2001, Bazes, 2006).
In this paper we report on the isolation and identification of a potential natural antifouling compound from a dichloromethane extract of S. muticum.

2. Material and methods
The brown alga Sargassum muticum (Yendo) Fensholt was harvested in Locmariaquer
(47.55°N-2.90°W, Brittany, France) in March 2004. After collection, the material was rinsed in 3 sterile seawater and 5 % ethanol in order to remove any associated microflora. Algae were then dried at room temperature under shade, and stored in the dark before use. Extraction was performed as previously described by Hellio et al (2001). The dried algae were suspended by stirring in ethanol 95° (2000 g/12 L). After decantation, the resultant pellet was re-extracted five times in the same way. The alcoholic extracts were combined and evaporated under vacuum at low temperature (35°C). Distilled water (4L) was then added and partitioned with dichloromethane (4x4L). The organic phases were collected, left dry in presence of Na2SO4 for 24 h, filtered and concentrated under vacuum at low temperature (dichloromethane extract). The resulting dichloromethane extract (A) was stored at 4°C before use. The extraction yield was 0.85%.

Biocides commonly used in commercial antifouling paints were also evaluated on marine
bacteria, microalgae and macroalgae spores. Diuron, Irgarol 1051, Tolylfluanid and
Dichlofluanid were provided by Nautix, France. Binders and paints. The binder used was purchased from ZENECA. It is a mixture of an acrylic copolymer (polybutylmethacrylate-co-polymethylmethacrylate) with rosin. The relative amount of rosin influences the erosion properties of the final paints. Paints were formulated with this polymer (cf. table I). All the ingredients were dispersed under vigorous agitation (2000rpm) for 1h. Then the paints were filtered through a 100 m sieve.

Immersion and test procedures. Test panels were coated by using an automatic film applicator (Sheen 1137). The wet films were 200m thick. After drying, plates were immersed in the harbour of Lorient (Britanny, France) for two months, July and August, when the fouling pressure is the highest. The plates were immersed under the surface, where most of the fouling organisms live. Purification of the active extract. For each step of purification, the different fractions were tested against three agents of microfouling. The most active fraction was retained for a further purification step. 1.5g of the dichloromethane extract (A) was added to a Solid Phase Extraction (SPE) column (Chromabond SiOH, 150 mL/50 g, Macherey-Nagel) previously conditioned with hexane. Elution was carried out using a gradient of CH2Cl2/MeOH from 99:1 to 0:100 (v/v). The resulting fractions were collected, evaporated and stored at 4 °C before use. The most active fraction (20 mg) was then laid on a preparative pre-coated TLC plate (SIL G-200, Macherey-Nagel) and eluted with CH2Cl2/MeOH 85:15 (v/v). After drying, part of the plate was revealed with sulphuric vanillin (1 g of vanillin in 100 mL of MeOH and 1 mL of concentrated sulphuric acid). Each spot was then scratched, dissolved in CH2Cl2/MeOH 85:15 (v/v), centrifuged and the supernatants were evaporated and stored at 4 °C before use. The active spot was investigated on a HPLC system (Dionex) with a 600E pump and an ASI-100 autosampler injector and UV detection at 215 nm. Separation was performed on an Econosil C18 (Alltech) column (10 mm ID x 250 mm L) heated at 30°C. A multi-step eluting gradient (MeOH/H2O 85:15 0-15 min, MeOH/H2O 100:0 15-30min, MeOH/H2O 85:15 30-40 min) was used at a flow rate of 3 mL.min-1. The volume used for each injection was 500μL. Each peak was collected, evaporated and stored at 4 °C before use. Identification of the active compound

4. Mass spectrometry experiments. An Agilent Technologies 1100 Series vacuum
degasser, LC pump and autosampler (Hewlett-Packard, Germany) were used to analyse the
fraction isolated after C18 HPLC. Twenty microliters of sample solutions were applied onto an analytical C18 reversed-phase column (Hypersil ODS, 250×4.6 mm, particle size 5 μm). The elution procedure consisted of an isocratic profile of methanol–water (15:85, v/v) for 5 min, followed by a linear gradient from 85 to 100% methanol over 15 min, and an isocratic profile with 100% methanol over 20 min. The LC flow (0.4 mL.min-1) was split (1/12) using a microsplitter valve (Upchurch Scientific, USA). The post-column additive, a mixture of 5 mM ammonium acetate and 0.05% trifluoroacetic acid (TFA) (Analysis grade, Carlo Erba) in methanol–water (50:50, v/v), was added using a Cole-Parmer (USA) syringe pump and a 2.5 mL SGE syringe at a flow-rate 150 μL.h-1. The LC-separated compounds were detected by electrospray ionization ion trap mass spectrometry (ESI-MS) using a Bruker Esquire-LC spectrometer (Bruker Daltonic, Germany) under positive-ion conditions. For each compound, two ions were formed: the [M+H]+ and the [M+Na]+ ions. The [M+H]+ ions were isolated for
MS–MS fragmentation. The MS–MS chromatographic analysis is segmented for the isolation and fragmentation of the eluted [M+H]+ ion. The electrospray used nitrogen as a nebulizing gas (pressure set to 15 p.s.i.) and a drying gas (flow set to 7 mL.min-1). The drying temperature was 300°C. The helium pressure in the ion trap was 6 x 10−6 mbar. Full-scan mode detection was used with a scan range from m/z 50 to 700. The software used was Bruker Esquire-LC NT version 6.08 and Agilent Technologies ChemStation May 1998.

NMR experiments. NMR experiments were performed at 25°C in a Bruker Avance DRX 500 spectrometer equipped with an indirect 5 mm triple TBI 1H/{BB}/13C probehead using standard pulse sequences available in the Bruker software. The samples were dissolved in 700 μL of 99.8% MeOD. 1D 1H spectra were recorded at 500.13Mhz with a 30° pulse, a delay D1 of 2s and 64 scans. Chemical shifts were expressed in ppm relative to TMS (Tetrametylsilane) as external standard. Double-quantum filtered 1H-1H correlated spectroscopy (DQF COSY), Heteronuclear multiple quantum coherence (HMQC), Heteronuclear multiple bond coherence (HMBC) with a 60 ms mixing time were performed according to standard pulse sequences to assign 1H and 13C resonances.

Gas chromatography experiments. Active fraction was evaporated under nitrogen and
methylated by contact with methanol/sulphuric acid (98:2, v/v) in excess for one night at 50°C. After cooling, 2 mL of pentane and 1 mL of water were added and vortexed. The upper organic phase was assayed using GC-MS on a Hewlett-Packard model 6890 series II gas chromatograph attached to an Agilent model 5973N selective quadripole mass detector. GCMS was connected to a computer with Hewlett-Packard chemstation and the ionisation voltage used was 70 eV at 250°C. The temperature of injector and interface were maintained at 250°C and Helium was used as a carrier gas under constant flow (1 mL.min-1). Separation was realised on a CP-Sil 5 CB low bleed MS (Chrompack; 60 m x 0.25 mm i.d., 0.25 μm film thickness). The oven temperature was programmed from 80 to 170 °C at a rate of 30 °C/min, then from 170 at 295 °C with a rate of 3 °C.min-1.

Bioassays
Antibacterial activities. The marine bacterial strain was obtained from the Culture Collection of the IUT of Quimper (LUMAQ, UBO, France) and identified by the CIMB (Institut Pasteur, Paris, France) as Rhodobacteraceae bacterium R11 A. This bacterium was associated with immersed surfaces and isolated from decomposing seaweeds (Hellio et al., 2004). Antibacterial evaluation of the extracts and fractions was performed in 96-well plates as previously described in Bazes et al (2006). Samples of cultures grown overnight (2 × 108 cells/mL) were incubated with extracts and biocides (at the concentration of 25, 50, 100, 200 and 300 μg mL− 1) for 48 h at 20 °C (Maréchal et al., 2004). All inhibition assays were carried out in triplicate. Growth was monitored by measuring OD600 with a Packard Spectracount microplate spectrophotometer and the percentage of inhibition was calculated for each concentration:

%inhibition=(ODc−ODc)/ODc×100

where ODc is the mean optical density of the bacterial controls and ODt is the mean optical density of the test samples. Control testing with the solvents and N-decane 1% was performed for every assay and showed no inhibition of the microbial growth. Seawater was used as a negative control.

Inhibition of phytoplankton growth.
Cylindrotheca closterium (Diatomophyceae, AC515) was obtained from the Culture Collection of Algae of the University of Caen (France). It was used as a common fouling species (Jackson, 1991, Hellio et al., 2004). Screening for bioactivity was performed as described by Sawant et al. (1995) and modified in Bazes et al (2006). The effect of algal extracts and fractions (at the concentration of 25, 50, 100, 200 and 300 μg mL− 1) was assessed after 72 h by estimating the chlorophyll-a (Aminot, 1983). All the screening experiments were carried out in triplicate. The percentage of growth inhibition was calculated:

%inhibition=(chlac−chlat)/chlac×100

where chlac is the mean concentration of chlorophyll-a of the algal controls and chlat is the mean concentration of chlorophyll-a of the test samples. Control tests with the solvents and N-decane 1% were performed for every assay and showed no inhibition of the microalgal growth. Seawater was used as a negative control.

Inhibition of germination of Ulva lactuca spores. Ulva lactuca (Ulvales, Chlorophyta) samples were collected in July and September 2004 at Locmariaquer, South Brittany, France (47°33’N, 02°56’W). Spores were obtained using the osmotic method (Fletcher, 1989). Tests of algal extracts and fractions on spores were performed as described by Hattori and Shiruzi (1996) and Bazes et al. (2006), by determining the percentage of inhibition of germination of spores (600/mL) in plastic Petri dishes after incubation for 5 days at 20 °C under 24 h light. All the screening experiments were carried out in triplicate. The percentage of growth inhibition was calculated:

%inhibition=(gsc−gst)/gsc×100

where gsc is the mean number of germinated spores for the controls and gst is the mean number of germinated spores for the test samples. Seawater was used as a negative control.

Toxicity
Cytotoxicity evaluation by cell viability was performed by the neutral red dye method
(McLaren et al., 1983) on 3T3 as described in Bazes et al. (2006). Cellular suspensions (3,5.105 3T3 cells mL− 1 purchased from Eurobio) were incubated with various concentrations of algae extracts and biocides (10–300 μg mL− 1, 4 wells per concentration) in 96-well plates (72 h, 37 °C, 5%CO2) in Eagle's MEM 10% FCS. The same experiment has been conducted with Vero cells. All the cytotoxicity experiments were carried out in triplicate. The cytotoxic concentration (CC50) was expressed by a percentage of destruction:

%destruction=(ODc−ODt)/ODc×100

where ODc is the mean optical density of the cell controls at 540 nm and ODt is the mean optical density of the test samples at 540 nm.

Statistical analysis
Percentage of growth inhibition was calculated for each microfouling organisms as described previously. The 50% effective concentrations (EC50) and cytotoxic concentrations (CC50) were estimated by regression analysis with Prism software, Version 4 (GraphPad Software, Inc.). All calculations were based on measured concentrations of extracts, and CC50 and EC50 were given when it was in the range of concentrations.

3. Results
In situ testing
Results of the in situ tests are shown on Figure 1. No barnacles or mussels were observed on the test rack. The paint including only copper is less efficient than the paints including the crude extract. When copper and crude extract are included together in the paint, there is much less fouling than on the other coatings. 37% of the plate painted with crude extract of S. muticum and copper are covered with young thalli of Ulva sp., while 92% of the plate painted only with S. muticum extract, and 100% of the plate painted only with copper are covered with different green algae (mostly from the genus Ulva), and red algae (mostly from the genus Polysiphonia). Well-developed thalli of Ulva sp. were observed on those last two plates.

Identification of the active compound
Solid Phase Extraction of the crude extract (A) allowed for the isolation of an active fraction in the CH2Cl2/MeOH 70:30 part (B) (91.5mg). The preparative TLC of that sample gave 8 fractions. Fraction no.5 (C) (22.8mg) was active and it was analysed by HPLC on a C18 column using a MeOH/H2O gradient as the eluent. After HPLC, ten fractions were isolated. The eighth one (D) (2.7mg of a pale green oil) was inhibitory to the growth of the three organisms tested. This last fraction was isolated in large quantities for the identification of bioactive molecules. MS on the D fraction showed a peak corresponding to two ions. The m/z 413.4 ion was found in majority while the m/z 391.4 ion was in minority, corresponding to the [M+H]+ and [M+Na]+ ions of the octyl phthalate. MS-MS detection was then used for dentification. The m/z 413.4 ion gave no signal in those conditions, while the m/z 391.4 ion produced a m/z 149 fragment, typically representative of phthalates.

NMR on the D fraction showed that protons from terminal methyl groups show one badly
defined triplet at 0.88 ppm (mainly from 16:0 acyl chains). A multiplet at 1.2 ppm is assigned to the methylene protons. The multiplet at 2.36 ppm corresponds to the CaH2 group and the signal at 1.58 ppm to the CbH2 group (where a and b positions are relative to the carbonyl group). Those signals reveal that this fraction is mostly constituted of lipid chains. The integration and the lack of unsaturated signals at about 5.5 ppm confirm that most of the lipid chains are 16:0 (palmitic acid). The HMQC spectrum allowed the specific assignment of 1J carbons and HMBC sequencing determined the shift of the carbonyl group. To confirm to the results obtained by NMR, and determine the abundance of fatty acids, GC-MS analyses were performed on every sample.

The fatty acid content of every sample is shown in Table 2. The crude extract contains 99% fatty acids and 1% contaminant. This table highlights that the different steps used during the purification process led to the loss of most of the fatty acids present in the crude extract, the only main one remaining in the D fraction. The analysis of fraction D confirmed the results obtained with NMR. As it was not possible to separate the two main compounds from the D fraction, palmitic acid and dioctyl phthalate were purchased from Sigma and were investigated separately for their antifouling activity in order to determine the role of each in the activity of the fraction

Antifouling activities of the different isolated fractions.
The antifouling activities of the crude extract, the HPLC purified fraction, the palmitic acid and dioctyl phthalate (Sigma) and commercial biocides were evaluated and are presented in Table 3. The remaining active fraction after the HPLC step (D) contains at least 70% palmitic acid and shows a better activity on every fouling organism tested than the four chemical biocides. Moreover, this fraction showed no toxicity on 3T3 cells. Palmitic acid purchased from Sigma was also tested for its antifouling activities and showed good antibacterial activity against R. bacterium R11A with an EC50 at 44μg.mL-1. Besides this antibacterial activity, palmitic acid also inhibits the development of a microalgal strain (C. closterium) at 45.5μg.mL-1 and the germination of spores from U. lactuca at 3μg.mL-1. Myristic (14:0) or stearic (18:0) acids were also tested on fouling organisms and none of them showed antifouling activity (data not shown).

Those results also show that palmitic acid has a better antibacterial activity than dioctyl phthalate while the dioctyl phthalate is inactive at concentrations up to 300μg.mL-1. However, the comparison of the activity of those two products on C. closterium shows that the dioctyl phthalate is more efficient than the palmitic acid with an EC50 lower than 25μg.mL-1. This EC50 is the same as for the crude extract. This suggests a synergetic effect between the dioctyl phthalate and the palmitic acid on the growth of C. closterium. The biocides tested here showed a low antibacterial activity. Diuron and Dichlofluanid showed an inhibition of Rhodobacteraceae bacterium R11 A at less than 200μg mL− 1, while Tolylfluanid showed no bacterial inhibition under 300μg mL− 1. Conversely, they all showed a good microalgal inhibition under 25μg mL− 1. Irgarol, Tolylfluanid and dichlofluanid showed less inhibition of the germination of the spores than the extracts and purified fractions, while Diuron was active at 25μg mL−1. The four biocides tested here showed high toxicity against 3T3 cells with a CC50 under 32μg mL−1, while no cytotoxicity was observed at oncentration lower than 300μg.mL-1 for the crude extract and purified fractions.

4. Discussion
In 2000, a study on the antifouling activity of extracts from 30 marine algae has been conduced (Hellio, 2000). Statistical analysis of this study allowed the isolation promising potential antifouling of extracts from the brown seaweed Sargassum muticum. This study was confirmed and completed by the work of Hellio et al. (2004), and the study from Bazes (2006) showed that the most efficient extract was produced from S. muticum harvested in March. The chemical composition of Sargassum has been studied extensively but the present investigation was undertaken considering that there is no report regarding antifouling activity of purified compounds derived from S. muticum.Palmitic acid is a common fatty acid in brown algae and in the genus Sargassum it can represent 20 to 40% of the total fatty acids (Vaskovsky et al., 1996, Li et al., 2002, Hossain et al., 2003, Kornprobst, 2005). In S. muticum it was shown to constitute 21.5% of the total fatty acids (Vaskovsky et al., 1996). Fatty acids can be produced from triglycerides by action of lipases and have to be included in chemical ecology studies (Noguchi et al., 1979). The fats and fatty acids from marine organisms can play an important role due to the wide diversity of their biological characteristics and their oxidative enzymes leading to the formation of many other bioactive secondary metabolites (Ganti et al., 2006). Indeed, some fatty acids have shown antibacterial or bacteriostatic activities (C8-C12), while C4-C12 fatty acids have antifungal activities and C7-C12 fatty acids inhibit the growth of Chlorella sp (Noguchi et al., 1979). Active antibacterial extracts from different brown algae (Alaria marginata, Desmarestia ligulata, Dictyota pfaffii, Egregia menziesii, Eisenia arborea, Fucus distichus, Laminaria saccharina, Macrocystis integrifolia, Nereocystis luetkeana and Pleurophycus gardneri) have been found to be made up of saturated and unsaturated fatty acids, with a predominance of myristic, palmitic, oleic, arachidonic and eicosapentaenoic acids (Rosell & Srivastava, 1987, Barbosa et al., 2007). A mixture of fatty acids from a lipophilic fraction from Skeletonema costatum, has also shown an interesting level of inhibition on the growth of Vibrio anguillarum and other pathogens associated with the aquaculture industry (Naviner et al., 1999). Hexadecyl palmitate isolated from the alcyonacean soft coral Sinularia polydactyla was also shown to be active against Vibrio harveyi (Risk et al., 1997). The sulphoglycerolipid 1-O-palmitoyl-3-O(6′-sulpho-α-quinovopyranosyl)-glycerol isolated from the methanolic extract of the brown seaweed Sargassum wightii is active against Xanthomonas oryzae. This compound is mainly formed from palmitic acid (Arunkumar et al., 2005).

A method developed to control biofouling using polyglycol fatty ester has shown that pure palmitic acid may be used to inhibit bacteria from adhering to a submergible surface (Glover et al., 1997). Those studies confirm the biological activity of palmitic acid observed in our work. The type and amount of free fatty acids can then have a role in the overall defence against microbial colonisation (Benkendorff et al., 2005), but we have shown here that a fatty acid can have an effect on other microfouling organisms. However, we have also highlighted the presence of the 1,2 benzenedicarboxylic acid, bis(2-ethylhexyl) ester (or dioctyl phthalate; di-(2-ethylhexyl)-phthalate or DEHP), which is a plasticizer and constitutes 16% of the active fraction of S. muticum. Pthalate esters are likely contaminants from plastics in the laboratory encountered during the extraction or isolation process and are commonly found during natural products isolation. However, phthalate ester may also come from the coastal environment and/or reflect a phenomenon of bioaccumulation (Peakall, 1975). Phthalate esters have been found in soils, plants, and aquatic organisms (Morris, 1970, Peakall, 1975, Melancon & Lech, 1976, Noguchi et al., 1979, Wofford et al., 1981, Stales et al., 1997, Chen, 2004, Mackintosh et al., 2004, Cho et al., 2005). Because of their lipophilicity, they can be potentially bioaccumulated by organisms (Mackintosh et al., 2004). The biosynthesis of di-(2-ethylhexyl)-phthalate has been studied by Chen (2004), who has shown that the red alga Bangia atropurpurea was synthesising this compound de novo. In algae, di-(2-ethylhexyl)-phthalate has been isolated from Ceramium rubrum, but the origin of this phthalate had not been elucidated (Noguchi et al., 1979). Dioctyl
phthalate has also been isolated from the brown algae S. wightii (Sastry & Rao, 1995), Ishige okamurae (Cho et al., 2005) and S. confusum (Ganti et al., 2006). The dioctyl phthalate isolated from S. wightii has shown antibacterial activity against Staphylococcus aureus, Proteus vulgaris, E. coli, Salmonella typhi, S. paratyphi A, S. typhiridium and Pseudomonasaeruginosa (Sastry & Rao, 1995). This phthalate was isolated in a lipid fraction, not unlike in our study. The other extracts of algae studied by those authors and harvested at the same place did not show any antibacterial activity (Sastry & Rao, 1994) which suggested that the antibacterial compound of interest did not come from the environment. Di-n-octylphthalate (DNOP) has been isolated from Ishige okamurae and tested against the mussel Mytilus edulis and the green alga U. prolifera (Cho et al., 2005). Total repulsion of the fussel feet was induced by 0.3mM of DNOP, and 1mM of DNOP showed a reduction of 7.5% in spore fixation compared to a seawater control. Dioctyl phthalate also has been isolated from S.confusum and tested on spore attachment of U. pertusa (Ganti et al., 2006). Concentrations of 1 to 100 μg.mL-1 inhibited 53 to 86% of spore attachment.

The role of the phthalate ester in the active fraction of S. muticum does not seem to be
important, except against the growth of the phytoplanktonic strain, but it would be interesting to determine its origin.

In conclusion, fatty acid esters can then play an important role in the defence and protection against bacterial development, providing that they can be present in sufficient quantities on the considered surface (Benkendorff et al., 2005). The relevant literature leads us to believe that palmitic acid could be responsible for the antifouling activity observed in the active fraction isolated from S. muticum. Two patents (Glover et al., 1997, Risk et al., 1997) already showed the potential of pure palmitic acid as an antibacterial compound which could be used 9 in wood protection (Risk et al., 1997), or of one of its derivate, hexadecyl palmitate, which could inhibit bacterial colonisation of a submersed surface (Glover et al., 1997). The tests conducted with commercial palmitic acid on representative organisms of primary colonisation, show good activity at low concentrations. Moreover, no toxicity was observed on the cell models used. This compound has potential for the development of an environmentally friendly antifouling product. Furthermore, it can be easily purchased, so there is no need to carry out expensive and time-consuming extractions from S. muticum. New assays in paints for commercial palmitic acid and D fraction are currently under development to compare their activity in vivo.

References
Abarzua S., Jakubowski S (1995). Biotechnological investigation for the prevention of
biofouling: I. Biological and biochemical principles for the prevention of biofouling. Mar. Ecol. Prog. Ser. 123: 301-312
Arunkumar K., Narayanan Selvapalam N., Rengasamy R. (2005). The antibacterial
compound sulphoglycerolipid 1-0 palmitoyl-3-0(6'-sulpho-alpha-quinovopyranosyl)-glycerol from Sargassum wightii Greville (Phaeophyceae) Bot. Mar. 48 (5): 441-445
Bakus G.J., Targett N.M. & Schulte B. (1986). Chemical ecology of marine organisms: an overview. J. Chem. Ecol. 12 (5): 951-987
Banaimoon S.A. (1992) Fatty acids in marine macroalgae from southern Yemen (Hadarmout) including occurrence of eicosatetraenoic (20:4) and eicosapentaenoic (20:5) acids. Bot. Mar. 35: 165–168.
Barbosa, J. P., Fleury B. G., da Gama B. A. P., Teixeira V.L., Pereira R.C. (2007). Natural products as antifoulants in the Brazilian brown alga Dictyota pfaffii (Phaeophyta, Dictyotales). Biochem. Syst. Ecol. 35 (8): 549-553.
Bazes A. (2006) Recherche et valorisation de principes actifs antifouling isolés à partir de trois macroalgues. Thèse de doctorat, Université de Bretagne-Sud.
Bazes A., Silkina A., Defer D., Bernède-Bauduin C., Quéméner E., Braud J-P., Bourgougnon N. (2006) Active substances from Ceramium botryocarpum used as antifouling products in aquaculture. Aquaculture 258 (1-4): 664-674
Benkendorff K., Davis A.R., Rogers C.N., Bremner J.B. (2005) Free fatty acids and sterols in the benthic spawn of aquatic molluscs, and their associated antimicrobial properties. J. Exp. Mar. Biol. Ecol. 316 (1): 29-44
Chambers L.D., Stokes K.R., Walsh F.C., Wood R.J.K. (2006) Modern approaches to marine antifouling coatings. Surf. Coat. Tech. 201 (6): 3642-3652
Chen C.Y. (2004) Biosynthesis of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) from red alga Bangia atropurpurea. Water Res. 38(4):1014-1018.
Cho J-Y, Choi J-S, Kang S-E, Kim J-K, Shin H-W, Hong Y-K . (2005) Isolation of antifouling active pyroglutamic acid, triethyl citrate and di-n-octylphthalate from the brown seaweed Ishige okamurae. J. Appl. Phycol. 17: 431-435
Critchley A.T., Farnham W.F., Yoshida T., Norton T.A. (1990) A bibliography of the invasive alga Sargassum muticum (Yendo) Fensholt (Fucales, Sargassaceae). Bot. Mar. 33: 551-562
Davis A.R., Targett N.M., Mc Connel O.J., Young C.M. (1989) Epibiosis of marine algae and benthic invertebrates : natural products chemistry and other mecanisms inhibiting settlement and overgrowth.In: Scheuer P.J., Editor, Bioorg. Mar. Chem. 3, Springer-Verlag, Berlin, pp. 85-114
Fletcher R.L. (1989) A bioassay technique using the marine fouling green alga Enteromorpha. Int. biodeterior. 25: 407-422
Fusetani N. (2004) Biofouling and antifouling. Natural Product Reports 21: 94–104
Ganti V.S., Kim K.H., Bhattarai H.D., Shin H.W. (2006) Isolation and characterisation of some antifouling agents from the brown alga Sargassum confusum. J. Asian Nat. Prod. Res. 2006, 8(4): 309-315
Glover D.E., Whittemore M.S., Bryant S.D. (1997) Methods and compositions for controlling biofouling using polyglycol fatty acid esters. International Patent Application WO 97/11912
Harlin M. (1996) Allelochemistry in marine algae. Crit. Rev. Plant. Sci. 5(3): 237-249
Harvey H.R., Kennicutt M.C. (1992) Selective alteration of Sargassum lipids in anoxic
sediments of the Orca basin. Org. Geochem. 18 (2):181-187
Hattori T., Shizuri Y. (1996) A screening method for antifouling substances using spores of the fouling macroalga Ulva conglobata Kjellman. Biofouling 8: 147-160
Hay M.E., Fenical W (1988) Marine Plant-Herbivore Interactions: The Ecology of Chemical Defense. Ann. Rev. Ecol. Syst. 19: 111-145
Hay M.E. (1996). Marine chemical ecology : what’s known and what’s next? J. Exp. Mar.
Biol. Ecol. 200: 103-134
Hellio C. (2000) Recherche de nouvelles substances à activité antifouling à partir de
macroalgues du Littoral Breton. Thèse de Doctorat Sciences de la Vie, Université de La Rochelle.
Hellio C., De La Broise D., Dufossé L., Le Gal Y., Bourgougnon N. (2001) Inhibition of marine bacteria by extracts of macroalgae: potential use for environmentally friendly antifouling paints. Mar. Environ. Res. 52: 231-247
Hellio C., Marechal J-P., Véron B., Bremer A.G., Clare A.S., Le Gal Y. (2004) Seasonal variation of antifouling activities of marine algae from the Brittany coast (France). Mar. biotechnol. 6(1): 67-82
Hossain Z., Kurihara H., Takahashi K. (2003) Biochemical composition and lipid compositional properties of the brown alga Sargassum horneri. Pakistan J. Biol. Sci. 6(17): 1497-1500
Jackson S.M. (1991) Microalgae: Their status as fouling organisms. Oebalia 17 (1): 295-303 Kornprobst J-M. Substances naturelles d’origine marine, Tome 1 : Généralités, microorganismes, algues. Tec & Doc, Paris, 2005.
Kubo I., Himejima M., Tsujmoto K., Muroi H., Ichikawa N. (1992) Antibacterial activity of crinitol and its potentiation. J. Nat. Products 55 (6):780–785.
Lambert S.J., Thomas K.V., Davy A.J. (2006) Assessment of the risk posed by the antifouling booster biocides Irgarol 1051 and diuron to freshwater macrophytes. Chemosphere 63(5): 734-743
Li X., Fan X., Han L., Lou Q. (2002) Fatty acids of some algae from the Bohai Sea.
Phytochemistry 59(2): 157-61
Mackintosh C.E., Maldonado J., Hongwu J., Hoover N, Chong A, Ikonomou MG, Gobas FA.
(2004) Distribution of phthalate esters in a marine aquatic food web: comparison to
polychlorinated biphenyls. Environ. Sci. Technol. 38(7): 2011-20
McLaren C., Ellis M. N., Hunter G. A. (1983) A colorimetric assay or the measurement of the sensitivity of Herpes simplex viruses to antiviral agents. Antivir. Res. 3: 223-234
Melancon M.J. Jr, Lech J.J. (1976) Distribution and biliary excretion products of di-2-ethylhexyl phthalate in rainbow trout. Drug Metab. Dispos. 4(2): 112-118
Morris RJ. (1970) Phthalic acid in deep sea jellyfish Atolla. Nature 227: 1264
Naviner M., Bergé J-P., Durand P., Le Bris H. (1999) Antibacterial activity of the marine diatom Skeletonema costatum against aquacultural pathogens. Aquaculture, 174: 15-24
Noguchi T., Ikawa M., Uebel J.J., Andersen K.K. (1979) Lipid constituents of the red algae Ceramium rubrum. A search for antimicrobial and chemical defense substances. In: Hoppa HA, Levring T., Tanaka Y., editors. Marine algae in pharmaceutical science. New York: Walter de Gruyter & co, pp. 711-718
Peakall DB. (1975) Phthalate esters: Occurence and biological effects. Residue Rev. 54: 1-41
Phillips D. (1977) The use of biological indicator organisms to monitor trace metal pollution in marine and estuarine environments-a review. Environ Pollut. 13 (4): 281-317
Plouguerne, E., Le Lann K., Connan S., Jechoux G., Deslandes E., Stiger-Pouvreau V.
(2006). Spatial and seasonal variation in density, reproductive status, length and phenolic content of the invasive brown macroalga Sargassum muticum (Yendo) Fensholt along the coast of Western Brittany (France). Aquat. Bot. 85 (4):337-346.
Risk M., Harrison P., Lewis J. (1997) Wood preserving composition. International Patent Application WO 97/34747
Rosell K, Srivastava L. (1987) Fatty acids as antimicrobial substances in brown algae. Hydrobiologia 151-152 (1): 471-475
Sastry V.M.V.S, Rao G.R.K. (1994) Antibacterial substances from marine algae : successive extraction using benzene, chloroform and methanol. Bot. Mar. 37 (4): 357-360
Sastry V.M.V.S, Rao G.R.K. (1995) Dioctyl phthalate and antibacterial compound from
marine brown alga Sargassum wightii. J. Appl. Phycol. 7: 185-186
Sawant, S.S., Sonak, S., Garg, A. (1995) Growth inhibition of fouling bacteria and diatoms by extract of terrestrial plant, Derris scandens (Dicotyledonae:Leguminocae). Indian J. Mar. Sci. 24 (4): 229-230
Sawidis T., Brown M.T., Zachariadis G., Sratis I.. (2001) Trace metal concentrations in marine macroalgae from different biotopes in the Aegean Sea. Environ Int. 27: 43-47
Sieburth, J.M, Conover J.T. (1965) Sargassum tannin, an anti-biotic which retards fouling. Nature 208: 52-53
Stales C.A., Peterson D.R., Parkerton T.F., Adams W.J. (1997) The environmental fate of phthalate esters: a literature review. Chemosphere 35(4): 667-749
Steinberg P.D. (1992) Geographical variation in the interaction between marine herbivores and brown algal secondary metabolites. In: V.J. Paul, Editor, Ecological Roles of Marine Natural Products, Cornell University Press, Ithaca pp. 51–92.
Steinberg P.D., de Nys, R., Kjelleberg, S. (1998) Chemical inhibition of epibiota by Australian seaweeds. Biofouling 12: 227-244
Subramonia Thangam T., Kathiresan K. (1991) Mosquito larvicidal effect of seaweed
extracts. Bot. Mar. 34 (5): 433–435.
Vaskovsky, V.E., Khotimchenko, S.V., Xia, B., Hefang L. (1996) Polar lipids and fatty acids of some marine macrophytes from the Yellow Sea. Phytochemistry 42: 1347-1356
Wahl M. (1989) Marine epibiosis : I. Fouling and antifouling : some basic aspects. Mar. Ecol. Prog. Ser. 58: 175-189
Wahl M., Kröger K., Lenz M. (1998) Non-toxic protection against epibiosis. Biofouling 12 (1-3): 205-226
Wofford H.W., Wilsey C.D., Neff G.S., et al. (1981) Bioaccumulation and metabolism of
phthalate esters by oysters, brown shrimp and sheepshead. Ecotox. Environ. Safe. 5(2): 202-210
Yebra D.M., Kiil S., Dam-Johansen K. (2004) Antifouling technology- past, present and future step towards efficient and environmentally friendly antifouling coatings. Prog. Org. Coat. 50: 75-104

Source :
Journal of Applied Phycology August 2009, Volume 21, Number 4, Pages 395-403
http://dx.doi.org/10.1007/s10811-008-9382-9
© 2009 Springer. Part of Springer Science+Business Media
The original publication is available at http://www.springerlink.com

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